U.S. Pat. No. 6,655,192, hereby incorporated by reference herein, describes a permeameter providing both normal and lateral permeability measurements on porous materials. The prior art permeameter has a base, a fluid chamber housing and a compression ring. The base has a recess. The recess is defined by a transverse wall and a cylindrical upper sidewall. The fluid chamber housing has an upper axially extending tubular section and an enlarged lower section. A piston is positioned within the upper tubular section which is axially moveable within the upper tubular section. A seal is provided between the head of the piston and the upper tubular section with an o-ring.